Carburetor



July 7, F. H. ROYvC-E' CARBURETOR Filed Jan. 16, 1929 2 Sheets-Shet l 7INVENTOR.

d4 da Julyn', 1931. I F H ROYCE 1,813,866

CARBURETOR Filed Jan. 16, 1929 2 Sheets-Sheet 2 @My/zw A TTORNEYKPatented July-1, 1931 UNITED STATES-.PATENT oFF-ICE rmrmrcxnmmxnorcn, ornnus'rnan, weer wrrrnamo, cnrcmisrnn, ENGLAND,

Assioma To noLLs ROYCE' LIMITED, or DERBY, ENGLAND CARBURETORApplication led January 16', 192,9, Serial-No. 832,969, and in GreatBritain January-24, 1,928.

4This invention has reference to carburetors for internal combustionengines, in connection with which thepower output of the engine isfrequently varying as in the case of a motor car engine. Itrelates tothe type generally known as expanding carburetors, that is to say, inwhich the air way past the orifice or orifices from vwhich the petrolissues l into the mixing chamber and the metering lo constriction or jetare automatically varied in cross section `area to meet the changingconditions.

In all such carburetors the objects aimed at are that the speed oftravel of the air past u the fuel orifice or oriiices should be as faras possible constant to ensure a constant atomization of the petrol orother liquid fuel and that the ratio of etrol, or other liquid fuel, toair should as ar as possible, be constant. It is also desirable that thetendency of the atomized liquid to 'condense and/or be deposited betweenthe mixing chamber and the cylinder should be reduced to a' minimum.

The main object of this invention is to attain these ends better thanhas been done in carburetors heretofore in use. The invention has thefurther objects of enabling a carburetor of the type to be constructedwith a straight through gas passage, of reducing friction of movingparts to a minimum, and reducing the possibility of particles of dustinterfering with the working of the carburetor.

For the purpose of securing thebe'st atom- I arrange several featuresvin combination, namely, that the main air supply shall pass through thethroat and 4not as in many carbu- 0 rotors be admitted beyond thethroat, and

thirdly 'that before issuinoa 'from such orifice f the' gasoline shallhave ibeen atomized means of an air-bleed device.

For the purpose of preventing deposit of gasoline during' the passage ofthe fuel mixture from the` throat to thev induction pipe I not onlysecurethe best eneral atomization and diifusionof the galsoV inethroughout the air suppiyby means aforesaid, but in addition arrange themechanical parts so that there ization of gasoline throughout the airsupplyk need be no obstruction in thepassage from the section on line4-4 of Fig. 2. Fig. 5' is ay part section on line 55 of Fig. 2, Figs. 3,4 and 5 being drawn to an enlarged scale'and Fig. 6 iis a sectionthrough Fig. 5 on the line 6 6.

ais the main casting constituting the main body of the carburetorcomprising the air in. let al, two coaxial circular orifices a2 and a3to form andy accommodate the throat, an inclined tunnel a4 extendingfrom the lower part of the air inlet to the top of the casting toaccommodate an air bleed suction devie,

a part a forming a cylindrical cavity for the reception of the meterindevice, the float ,tank c of quasi vhorse s hoe s ape (embracing theupper half "of the air inlet, the orifice a2, the inclined tunnel, themetering device hereinafter described," and a tube containing aconnecting rod hereinafter described) and fan extension a" having a Hatupper surface and with an opening to the air avto support other partshereinafter Deferred to. a is a hole connesting the said 'tunnel andsaid cavity. The fixed member of the throat is formed in two arts, towit, by the curved walls of the orice a2, and the tuhuiar part b which'is 'threaded screwed into the casting ca 'b1 is a tuhuiar member secured:by bolts (not shown) to the .sting c, b2 the throttle valveand t `theinductionpipe provided with a heating gieelret. e is the moving memberof the throat.' c1 a sieeve threaded for part of its iength and screwedinto the member c, supporting a divided annular member c2, andtelescopically slideabie over the upstandingy sieeve cs of the memberet, which is seated iny `the vorice a? inthe casting a, and held inposition by means of .the member` c5 which rests, on one side, on ashoulder formed ou the casting aand, on the other side, is secured bymeans of shank c'i pivotally hingedon the casting a, and formed with athread, engaging a slot in the member 05, and having'the buttery nut Sscreened thereon. d and d1 are two oats in the fioat tank attached to aspindle dprovided'with projecting jaws da which enga-ge the valve needledi'. e is a tubu lar member, the lower part of which is of irregularcross section shape as shown in Figure 2, and the upper part of which isa cylindrical shape, being e1 of Fig. 1, mounted on the part al of thecasting a, and formed with a downward projecting cylindrical part c2which tits into a hole in the part a". e3 is a piston slideable in thecylindrical part e1 With a downward projecting cylindrical part e4 whichslideably lits for part o1c its length in, and is guided by thecylindrical projection e2. eis a diaphragm across the piston es. e are arow of holes through the wall of the said piston. e7 1s a coverenclosing with an air tight joint the upper end of the cylindrical parte1. e3 is a member to secure the cover el held in position on one sideby the shoulder e9 and on the other side by a rod el", swinging on apivot e, and engaging alslot e formed in the member es, and the butteriynut e. e14 is al spring reacting between cover e7 and diaphragm e5. Themember e is secured to part a7 by setscrews e (see Fig. 2) f are anumber of holes through the fixed member of the choke communicating withan annular s ace 1 which is in communication with the interior of thecylindrical parte1 via the conduits f2 and f3. g is a rod pivotallyhinged at the upper end to the cylindrical projection c4', and at thelower end to one arm of the lever g1, rocking on a fulcrumy'2 be-r tweenand supported by two' ears g (one only shown) on the casting a, theother end of which lever is pivotall hinged at g8 to a rod g which isconnected y a ball and socket joint g to the moving member c of thechoke. y The diffuser now to be described is contained in thetunnel aLof the casting a. h is a plug with a cylindrical part h? externallythreaded engaging a tapped thread in the tunnel at, 71.2 and h? aretubes within the tunnel a4| and cofaxial therewith, forming the annularspaces or conduitsh'i' and h5, the space h4 terminating at the upper endagainst Y the part h1 and the space h5 being in free communication atits upper end with the inside of the tube k3 which is in freecommunication atv its lower end with the air, k6 are rows of holesthrough the wall of the tube k2, It? an annular space around the tubeh2, ha a conduit, it an annular space in the fixed member of the throat,and hm aI row V of holes leading to the mixing chamber. f

The metering device is constructed as follows l z' is aptubular memberhavin a narrow diameter part il which fits into t e cavity in part a5 ofthe casting a, and an enlarged part 2 externally threaded to engage athread tapped in the casting a, and having a row of holes is through itsWall. t is a valve needle tapered at its lower end, and at its upper endshaped to receive the cylindrical end 5 of a lever e hereinafterdescribed. The lever G rocks on a pivot i7 projected ec centrically froma shaft i8 (see Figs. 5 and 6) and is actuated by a'push rod ifextending through a tube im passing through holes in the casting a andexpanding at each end to make a tight lit therein. The push rod at itslower end is a loose lit in a hollow plug @'11, inserted in tube 1 andis provided with a flat terminal which rests on a roller 1112 rotatingon a pivot projected from. the lever g1 and at its upper end is providedwith aA spherical end 14 which engages a spherical socket 15 in thelever 6. 4

The hand control is illustrated in TFigures 5 and 6. i

j is a hollow bracket, having a part jl cut away to receive the end otthe lever i, secured to casting a by stud j5 and located by dowel pin'54 and with a hole 555 therethrough tangential to, but with halitsdiameter within, the bore of the bracket. The shaft 8 has an annulargroove corresponding to the hole j, and when assenibled'in the bracketis secured by a screw j", j? is a lever secured to the shaft andactuatable by the driver.

Referring to Fig. 4, J is a bracket secured by set screw k1 tothecasting a and located bydowel pin k2, 7c3 is a coil spring reactingon the needle of the metering valve against the reaction of the lever 8.v

The 'functioning of the carburetor is as follows Gasoline from the floattank passes thence through the 'hole a to the air bleed suction deviceentering the annular space h4 and flowing through the holes It@ fills(to the gasoline level in the tank) the' annular space h5. When' theengine is .running the Gasoline 'm the spaces/L4 and h5 (atomized Ey airpassing up the tube h3 down the space h5 and through holes he)passesinto the annular space L" and via. the conduit it@ an nular spaceit and holes h1 to the mixing chamber. l J

The vacuum in the mixing chamber is communicated to the cylindricalparte1 by way of the passages f2, f3, whereupon the piston e3 is liftedagainst the reaction of spring e14 and through the medium of the leverg1 and rod g4 the moving member of the throat 0 is drawn down, andthrough the medium of the rod 2' and the lever i the needle i* is liftedthus allowing a greater quantity of air and gasoline to be supplied tothe engine. The arran ement of the vacuum cylinder e1 and the pistontherein is such that there is no suddenv movement. The space between'`the piston and the rbottomy p-art of thecylinder 'e1 is not directlyvented, and Vuntil air has v'passed throngl'i'-holes e6 and vleakedthrough the clearance between the cylinder wall and the piston, themovement oi the piston is delayed.

When the hand control is-exercised the ulcrum l is raised or loweredthereby lowering or raising the sphere end of the lever if" and with itthe'needle of the metering valve.

obstructed passage from the throat to the The construction enables astraight and unthrottle to be provided thus reducing unintentionalthrottling of the mixture supply,

- and secures in a new and improved manner a constant speed o airpastthe gasoline issuing orifices, with a resulting predetermined proportionof air and gasoline, and a varying supply of gasoline and air to meetvaryingconditions of engine speed and throttleI opening, and further ahandcontrol which while altering the proportion of gasoline to air doesnot disturb the required varying of supply. Further the friction' ofmoving parts` is reduced to a minimum. i

What I claim is 1. A carburetor for an internal combustion enginecomprising a throat consisting of an annular fixed member and 'a movablemember of circular cross section adapted to move co-axiall towards oraway from such annular mem er, a mixing chamber, a variablemetering jet,an air bleed suction device arranged and adapted to vaporize the liquid.fuel between the meterin and mixing chambers and means indepen ent ofthe pressure of air on the movable member for automatically adjustin themembers of the throat relatively and t e variable 4metering jet bothconsistently wlth-the vacuum in the mixingl chamber.

2. A carburetor for an internal combustion engine comprising a throat.consisting of an annular fixed member and a. movable member of circularcross section adapted to move coaxially towards or away from suchannular member, one air way and thatthrough. the

v throat, a mixintg chamber, a variable metering jet, an air 1 leedsuction device arran ed and adapted to .vaporize'the liquid fuel etweenthe metering and mixing chambers and means independent of the pressureof air on vmoved co-axially towards or away from ysuch annular member, athrottle valve, a mixing chamber consisting of a cylindrical passage way'from the throat to the induction pipe cov Fe axial with the throat andunobstructed except for thethrottle valve, a variable metering jet, anair bleedisuction device arranged and adaptedl tov vaporize the liquid:fuel betweenlthe metering and mixing chambers and means independent ofthe pressure oi' air on themovable member` for automatically adjustingthe members of the throat,rela-l atively andthe variable meteringjet.consistently with the vacuumin the -mixingg chamber.,

t. A carburetor for internal combustion engines comprising an'airway, athroat lconsisting of an annular-venturi projecting from the wall of'the air-way anda streamlined movable member adapted to be moved co-`axially towards or away. from such annular member, a mixing cham r, avariable metering jet, an air bleed suction device arranged and adaptedto vaporize the liquid fuel between the metering and mixing chambers andmeans independent of the pressure oi air on the movable member forautomatically adjusting the members yof the throat relatively land the ivariable metering jet consistently with the vacuum in the mixingchamber..

5. A carburetor as claimed in claim l, having a,- number of gasolineorifices issuing from the side of the annular venturi at the highestpoint of such venturi. f

(iQ-A carburetor for internal combustion engines comprising a throatconsisting of an annular fixed member and a movable member of circularcross section adapted to be moved co-axially towards or away from suchannular member, a float tank, a variablermetering jet, consisting of. apipe through. which the gasoline passes in its passage from the lloattank and a taper ended rod slidable in such pipe to obstruct, asrequired, the passage way therethrough, 'an air bleed suction 'devicearranged and adapted to vaporize the lliquid fuel between the meteringand mixing imil nchambers andmeans, independent of the pressure of airon the movable member, for

automatically adjusting the members ofthe l throat relatively and thevariable metering jet, consistently with the vacuum in the mixingchamber. I

A carburetor for an 1nternal combus tion engine comprising a throatconsisting of an annular fixed member and a movablemember of circularcross section adapted to be moved co-axially towards or away `from.suchnannular member, a variable metering jet, an'- air bleed suctiondevice arran ed and adapted to vapori'ze the li uid fuel etween themetering and mixing c mbers,"consist. ing of a central andv twocol-axial, spaced apart, upstanding pipes, the intermediate pipe having"a number of circumferentialv rows of holes therethrough, the centralpipe" being open at ,the 'lower' end to the air, the central andintermediate `pipe being in free communication, but otherwise enclosedat the upper end, the spaces between the central and intermediate andthe intermediatel and outer pipes being closed at the lower end, theouter pipe being at its upper endin direct communication with theissuing orifices, and

means, independent of the pressure of air on the movable member, forautomatically ad- A annular member, a mixing chamber, a variablemetering jet, an air bleed Vsuction de-' vi'cearranged and adapted tovaporize the liquid fuel between the metering and vmixing chambers,and`means, independent of the rpressure of air on the movable member,*for automatically adjusting the members of 'the throat relatively andthe variable metering Ajet consistently with the vacuum in the mixingchamber, the means for actuating the moving throat member, consisting ofa piston in a closed chamber one side of whi h is in communication withthe mixing chamber, and the other side, by restricted air leaks, open tothe air, a lever rocking on a -ulcrum intermediate its ends, one endbegin operatively connected to the piston and the other end o erablyconnected to the moving member o the throat, and the means for actuatingthe metering valve consisting of another lever pivotally ipulcrumed atone end, its Afree end actuating the said valve against the reaction ofa spring and a pushI rod engaged by the iirst said lever and actuatingthe sec-- ond said lever.

9. A carburetor as claimed in ciaim 8, with a hand operated controlvarying the ratio of, but not the automatic variability of the gasolinesupply.

1G. A carburetor as claimed in claim number 8, with a hand. operatedcontrol varying the ratio of, but not the automatic variabilasians@l ingjet'consistentlywith the 'vacuum in the mixing chamber, a number ofgasoline oriices issuing from the venturi in the plane of its highestpoint, the means for actuating themoving throat member consisting of apiston in a closed chamber, a circumferential row of holes issuing fromthe Venturi member of the throat in substantially the same plane as theasoline issuing'4 orifices communicating with onex side of the saidpiston, a series of restricted air leaks communicating with the otherside of the said piston, a lever rocking o n aifulcrum intermediate itsends, one end being operatively connected 'to the piston and the other.end operably connected to the moving member of the throat, and themeans for actuating the metering valve consisting of another. leverpivotally fulcrumed at one end, its free end actu-ating the said valveagainst the reaction of a spring and a push rod engaged by the saidleverand actuating the second said lever.v

In testimony whereof I have hereunto affixed my signature.

' FREDERICK HENRY ROYCE.

ity, comprising a shaft on which the lever actuating the metering valveis mounted eccentrically and a lever projecting from such 'shaftoperable by the driver.

l1. A carburetor for an internal combustion engine comprising an airway,a threat consisting of an annular venturi progected from the wall of.the airway and a movable member oi circular cross section adapted to bemoved fao-axially towards or away from such .annular member, a mixingchamber, a

' variable'metering jet, an air bieed suction devicel arrangedy andadaptedto vaiporize the liquid fuel between the metering and mixingchambers and means inde endent of the pressure ci air on the Inovab emember for automatically adjusting the members-oi the throat relativelyand the variable meter-

